These 1-Edge Cutter Bits for Kwik-Way Boring Bars fit model numbers F, FT, FL, FN, FR, FS, FW, FWS, FWSII and FX. Choose between a Roughing Cutter (KWL-R) and a Finish Cutter (KWL-F). Both of the 1-Edge Cutter Bits has a 5/16" diameter and are designed to fit Kwik-Way OE Holders.